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Wyświetlanie 1-15 z 44
Tytuł:
Diversity of scoring, ingenuity of striking, art of flying - conceptual and systematical identification of soccer scoring techniques
Autorzy:
Zhang, Xiang
Shan, Gongbing
Liu, Feng
Yang, Shenglai
Meng, Mingliang
Powiązania:
https://bibliotekanauki.pl/articles/1933083.pdf
Data publikacji:
2021-05-05
Wydawca:
PPHU Projack Jacek Wąsik
Tematy:
scientific-based training system
biomechanics
anatomy
goal repeatability
aerial shots
Opis:
The terms of soccer scoring techniques (SSTs) used in practice and research have been remaining confusing; even dramatic, we still do not know how many SSTs available for the game. This scenario hinders not only the scientific studies on some unique SSTs but also the development of novel coaching methods for learning these SSTs. The current paper aims to bridge the gap by establishing a SST terminology system. The system is built based on goal repeatability, selected anatomical & biomechanical parameters, and analyses of 579 attractive goals from international professional tournaments. The results have revealed that there are 43 SSTs existed in current soccer practice. Some SSTs can be identified by preliminary parameters (i.e. anatomical parameters, the ball vertical position at the shot and the hit-point on the ball), but most of them need additional biomechanical examination on the movement control in frontal & transverse planes, jumping control, and trunk orientation at shots in order to identify uniquely. Further, the new SST terminology has disclosed that soccer attractiveness is linked to the diversity, ingenuity and artistry of shots. The most attractive type of scoring awaited by millions of spectators is aerial shots. Lastly, the most important contribution of the new SST terminology system is to help researchers and practitioners launch target-orientated studies that would provide a practical and convincing scientific coach-method, clear definitions, and means to reevaluate and improve SSTs in practice.
Źródło:
Physical Activity Review; 2021, 1, 9; 79-92
2300-5076
Pojawia się w:
Physical Activity Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectral Conditions for Graphs to be k-Hamiltonian or k-Path-Coverable
Autorzy:
Liu, Weijun
Liu, Minmin
Zhang, Pengli
Feng, Lihua
Powiązania:
https://bibliotekanauki.pl/articles/32083834.pdf
Data publikacji:
2020-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
spectral radius
minimum degree
k -Hamiltonian
k -path-coverable
Opis:
A graph G is k-Hamiltonian if for all X ⊂ V (G) with |X| ≤ k, the subgraph induced by V (G) \ X is Hamiltonian. A graph G is k-path-coverable if V (G) can be covered by k or fewer vertex disjoint paths. In this paper, by making use of the vertex degree sequence and an appropriate closure concept (due to Bondy and Chvátal), we present sufficient spectral conditions of a connected graph with fixed minimum degree and large order to be k-Hamiltonian or k-path-coverable.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 1; 161-179
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation and optimization of use of anionic collectors in direct flotation of bauxite ores
Autorzy:
Liu, C.
Feng, A.
Guo, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110801.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bauxite
collector
direct flotation
Opis:
Bauxite is the main raw material for the alumina industry. Direct flotation is the most widely used method for bauxite beneficiation. In this study, a large number of direct flotation tests were carried out using several anionic reagents. The testing concluded that vegetable oil acid (VOA), naphthenic acid (NA) and lauryl polyoxyethylene phosphate (AEP12) were the three outstanding collectors for bauxite direct flotation. ZMC collector was mixed and prepared using VOA, NA and AEP12, in which the mass ratio of VOA, NA and AEP12 was 1:1:0.5. When processing the bauxite ores of the mass ratio of Al2O3 to SiO2 (A/S) = 4.99, the A/S of the final concentrate was 7.08 and the recovery of Al2O3 was 90.22%. When processing ores of A/S = 4.5, the A/S of the final concentrate was 7.04 and the recovery of Al2O3 was 92.16%. Thus, it can be seen that properties and behaviors of the ZMC reagent were remarkable and met the demands of the “Lime-Bayer Process”.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 2; 932-942
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of ammonium sulfate on the sulfidation flotation of malachite
Wpływ obecności siarczanu amonu na przebieg procesu sulfitacji (siarczkowania) w trakcie flotacji malachitu
Autorzy:
Liu, C.
Feng, Q.
Zhang, G.
Powiązania:
https://bibliotekanauki.pl/articles/220224.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
malachit
siarczek amonu
flotacja poprzez sulfidację (siarczkowanie)
budowa powierzchniowa
malachite
ammonium sulfate
sulfidization-flotation
surface morphology
Opis:
The effect of ammonium sulfate on the sulfidation flotation of malachite was investigated by micro-flotation tests, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) measurements. Micro-flotation results show that the sodium sulfide concentration and strring time are difficult to control on the sulfidation flotation of malachite. However, when ammonium sulfate was used, the detrimental effect of mixing time and high dosage of sodium sulfide on the sulfidization flotation of malachite can be efficiently eliminated. SEM results showed that sulfidized film on malachite in the presence of ammonium sulfate, and EDS analysis results showed that more S element absorbed and distributed equality on the malachite surface, which was agreed well with the macro-flotation results.
Badano wpływ siarczanu amonu na przebieg procesu siarczkowania w trakcie flotacji malachitu przy wykorzystaniu badania mikroskopowego, mikroskopii elektronowej skanningowej (SEM) oraz pomiarów spektrometrycznych rozpraszania energii EDS. Testy mikroskopowe wykazały, że stężenie siarczku sodu i długość czasu mieszania są parametrami, które niezwykle trudno kontrolować w trakcie procesu siarczkowania towarzyszącemu flotacji malachitu. Z kolei przy zastosowaniu siarczanu amonu, udaje się skutecznie wyeliminować niekorzystne efekty związane z czasem mieszania oraz wysokimi stężeniami siarczku sodu w trakcie flotacji malachitu poprzez siarczkowanie. Wyniki mikroskopii skaningowej wskazują, że przy zastosowaniu siarczanu amonu powstaje cienki film siarczkowy na malachicie zaś pomiary spektrometryczne wykazały większe ilości zaabsorbowanej i bardziej równomiernie rozłożonej siarki pierwiastkowej S na powierzchni malachitu, co pozostaje w pełnej zgodności z wynikami uzyskanymi z badania procesu flotacji w skali makro.
Źródło:
Archives of Mining Sciences; 2018, 63, 1; 139-148
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Efficiency Covering Technology for Covered Yarn Production: Controlling the Spandex Yarn Draw Ratio
Wysokowydajna technologia produkcji przędzy oplatanej z zastosowaniem kontroli współczynnika rozciągania przędzy spandexowej
Autorzy:
Feng, Pei
Liu, Dashuang
Yang, Chongchang
Powiązania:
https://bibliotekanauki.pl/articles/233862.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
tension controlled
elastic fibre
draw ratio
spandex covered yarns
naprężenie kontrolowane
włókno elastyczne
współczynnik rozciągania
przędza pokryta spandeksem
Opis:
This paper proposes a new covered yarn system in which the tension of spandex elastic yarn drawing is controlled. By analysing the relationship between the draw ratio and yarn tension, it was verified that the new tension controlled drawing system is feasible and results in yarns of superior quality and process stability.
W pracy zaproponowano nowy system wytwarzania przędzy oplatanej, w którym kontrolowane jest naprężenie rozciągania przędzy elastycznej spandex. Analizując zależność między współczynnikiem rozciągania a naprężeniem przędzy, zweryfikowano, że zaproponowany system ciągnienia z kontrolowanym naprężeniem jest wykonalny i zapewnia wytworzenie przędzy o najwyższej jakości z zachowaniem stabilności procesu.
Źródło:
Fibres & Textiles in Eastern Europe; 2020, 6 (144); 24-28
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of pH on surface characteristics and flotation of sulfidized cerussite
Autorzy:
Feng, Q.
Wen, S.
Zhao, W.
Liu, J.
Liu, D.
Powiązania:
https://bibliotekanauki.pl/articles/110234.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
cerussite
sulfidization
excessive sulfide ions
pH
surface analysis
Opis:
The effect of pH on surface characteristic and flotation of sulfidized cerussite was studied by micro-flotation tests, dissolution experiments, scanning electron microscopy (SEM) energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). The micro-flotation tests demonstrated that higher recovery of cerussite was achieved in acidic solutions than that in alkaline solutions. Despite the addition of high collector concentrations, cerussite flotation did not improved in alkaline solutions. The dissolution performance of sulfide-treated cerussite at different pH values indicated that the lead sulfide layer on the surface of sulfide-treated cerussite could exist in acidic solutions and it was more stable at acidic pH than in alkaline solutions. This finding was proved by the SEM-EDS and XPS analyses.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 2; 676-689
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication, Structural Characterization and Optical Properties of the Flower-Like ZnO Nanowires
Autorzy:
Feng, L.
Liu, A.
Ma, Y.
Liu, M.
Man, B.
Powiązania:
https://bibliotekanauki.pl/articles/1538755.pdf
Data publikacji:
2010-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Bc
81.05.Dz
81.10.Aj
Opis:
Multipod flower-like zinc oxide (ZnO) nanowires have been successfully synthesized on Si(111) substrates using a pulsed laser deposition prepared Zn film as "self-catalyst" by the simple thermal evaporation oxidation of the metallic zinc powder at 850°C without any other catalysts or additives. The pre-deposited Zn films by pulsed laser deposition on the substrates can promote the formation of the ZnO nuclei effectively. Also it can further advance the growth of the flower-like ZnO nanowires accordingly. X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, Fourier transform infrared spectrum, and photoluminescence were used to analyze the structure, morphology, composition and optical properties of the as-synthesized products. The results demonstrate that the nanowires were single crystalline with hexagonal wurzite structure, grown along the [0001] in the c-axis direction. Room temperature photoluminescence spectrum of the ZnO nanowires shows a nearband-edge ultraviolet emission (peak at ≈ 384 nm) and a deep-level green emission (peak at ≈ 513 nm). In addition, the growth mechanism of the flower-like ZnO nanowires is discussed in detail.
Źródło:
Acta Physica Polonica A; 2010, 117, 3; 512-517
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comminution behavior and mineral liberation characteristics of low-grade hematite ore in high pressure grinding roll
Autorzy:
Cao, Jincheng
Liu, Lei
Han, Yuexin
Feng, Ansheng
Powiązania:
https://bibliotekanauki.pl/articles/110727.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
low-grade hematite ore
high pressure grinding roll
comminution behavior
degree of liberation
Opis:
The comminution process and mechanism of low-grade hematite ore in a high pressure grinding roll (HPGR) were investigated in this work. Three different methods were used for comminution of the hematite ore: HPGR with an air classifier, HPGR with screening followed by ball milling (HPGR+BM), and cone crushing with screening followed by ball milling (CC+BM). In addition, the effects of comminution methods on the degree of liberation of minerals in the grinding products were compared. The results suggest that the comminution process of the ore can be divided into four stages: appearance of tiny cracks, expansion of tiny cracks, which eventually form microcosmic cracks, development of principle cracks, and generation of the conjugate fracturing zone. Intergranular cracks, including partial intergranular cracks and complete intergranular cracks, are apparent in the comminution products of the HPGR. The complete intergranular cracks mainly occur in the conjugate fracturing zone, while the partial intergranular cracks within the particles result in an abundance of locked-particles in the comminution products. Furthermore, the degree of liberation of minerals is more influenced by the final grinding mode rather than the crushing method. It is found that complete intergranular cracks in the conjugate fracturing zone play a significant role in increasing the degree of liberation of iron minerals in the fine size fraction. The “mosaic-type” locked-particles have negligible effect on the liberation properties of iron minerals during the subsequent grinding process.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 575-585
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Ag nanoparticles-reinforced polyamide 6 nanocomposites by in situ polymerization and investigation of its properties
Autorzy:
Xu, Q.
Feng, X.
Liu, J.
Gong, P.
Powiązania:
https://bibliotekanauki.pl/articles/778762.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
In-situ solution polymerization
Ag nanomaterials
nanocomposites
crystallization properties
mechanical properties
Opis:
Polyamide 6 (noted as PA6)/Ag nanocomposites were prepared by an in situ solution polymerization method. AgNO3  was used as filler and was directly reduced to silver nanoparticles resulting in uniformly dispersed nanoparticles in the PA6 matrix. The thermal stability, crystallization, melting performance, and dispersion properties of the PA6/Ag nanocomposites were studied using transmission electron microscopy (TEM), thermogravimetric analysis (TG), differential thermal scanning calorimetry (DSC), X-ray diffraction (XRD), and polarized light microscopy (POM). Furthermore, the mechanical and tribological behaviors of as-prepared nanocomposites were evaluated using universal tensile testing, impact testing, and friction testing machines. The results show that Ag-nanoparticles are evenly dispersed in PA6 and decrease in size with increasing Ag content. Whereas the crystallinity increased with increasing Ag content, the crystallization temperature of the nanocomposites did not change significantly. However, the mechanical and tribological properties of the nanocomposites increased compared with pure PA6.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 4; 36-40
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on flotation behavior and mechanism of separating chalcopyrite and Molybdenite with ethyl mercaptoglycolate as inhibitor
Autorzy:
Yang, Xiao-Feng
Xu-Zhao
Liu, Yao-Yao
Powiązania:
https://bibliotekanauki.pl/articles/24085868.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ethyl thioglycolate
chalcopyrite
molybdenite
inhibitor
separation
Opis:
The effect of ethyl thioglycolate organic small molecule inhibitors on chalcopyrite molybdenite flotation behaviour is investigated via single mineral micro-flotation tests, zeta potential tests, and X-ray photoelectron spectroscopy (XPS) analysis. Results of the flotation test indicate that ethyl thioglycolate organic small-molecule inhibitors can effectively separate Cu and Mo and selectively inhibit chalcopyrite under weak alkaline conditions. Infrared spectroscopy and XPS analysis show that hydrophilic functional groups C=O and -COOH in the ethyl thioglycolate organic small molecules can chemically adsorb onto the chalcopyrite surface. Moreover, ethyl thioglycolate has no obvious effect on zeta potential of molybdenite. Therefore, ethyl thioglycolate can effectively separate chalcopyrite and molybdenite.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 2; art. no. 162824
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution of the Polymer Melt Velocity and Temperature in the Spinneret Channel of Bi-component Fibre Melt Spinning: a Mathematical Model
Autorzy:
Feng, Pei
Liu, Dashuang
Zhang, Ronggen
Yang, Chongchang
Powiązania:
https://bibliotekanauki.pl/articles/2056290.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
composite fibre
spinning assembly
velocity field distribution
mathematical model
Opis:
For the stability of composite fibre spinning, the difference in and distribution of the polymer melt velocity during the spinning are among the factors of importance. Based on the basic equation for the control of composite spinning dynamics, boundary conditions are identified and reported in this paper. A mathematical model for the symmetric and asymmetric distribution of the melt flow velocity in the microhole of the spinneret of the composite spinning assembly was developed. The accuracy of the mathematical model was also ascertained. It gives a theoretical basis for the designing of a composite spinning assembly.
Źródło:
Fibres & Textiles in Eastern Europe; 2021, 6 (150); 49--53
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Investigation of the Propagation Characteristics of Surface Transverse Wave Considering Various Quartz Substrate and Electrode Configurations
Autorzy:
Jiang, Chao
Cao, Xiaoli
Yang, Feng
Liu, Zejun
Powiązania:
https://bibliotekanauki.pl/articles/31339822.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
surface transverse wave
STW
interdigital transducer
IDT
finite element analysis
FEA
quartz
Opis:
Featured with a higher velocity, increased power handling capability, and better aging behavior, surface transverse wave (STW) shows more promising prospects than Rayleigh wave nowadays in various sensing applications. The need to design, optimize, and fabricate the related devices motivates the development of modeling and simulation. For this reason, a three-dimensional (3D) finite element (FE) simulation of STW on quartz, considering the crystal cut angle and the electrode effects, is presented in this study. Firstly, we investigated the effects of quartz’s cut angle on the generated waves. Here, the polarized displacements were analyzed to distinguish the wave modes. Secondly, the investigations of the electrode effects on the polarized displacement, phase velocity, and electromechanical coupling factor (K2) were carried out, for which different material and thickness configurations for the electrodes were considered. Thirdly, to examine the excitation conditions of the generated waves, the admittance responses were inspected. The results showed that not only the crystal cut angle but also the density and the acoustic impedance of the interdigital transducer (IDT) material have a strong influence on the excited waves. This article is the first to analyze STWs considering quartz’s cut angle and electrode effect through a 3D FE model. It could provide a helpful and easy way to design, optimize, and fabricate the related surface acoustic wave devices.
Źródło:
Archives of Acoustics; 2023, 48, 3; 403-412
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphs Whose Aα-Spectral Radius Does Not Exceed 2
Autorzy:
Wang, Jian Feng
Wang, Jing
Liu, Xiaogang
Belardo, Francesco
Powiązania:
https://bibliotekanauki.pl/articles/31566069.pdf
Data publikacji:
2020-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Aα -matrix
Smith graphs
limit point
spectral radius
index
Opis:
Let A(G) and D(G) be the adjacency matrix and the degree matrix of a graph G, respectively. For any real α ∈ [0, 1], we consider Aα(G) = αD(G) + (1 − α)A(G) as a graph matrix, whose largest eigenvalue is called the Aα-spectral radius of G. We first show that the smallest limit point for the Aα-spectral radius of graphs is 2, and then we characterize the connected graphs whose Aα-spectral radius is at most 2. Finally, we show that all such graphs, with four exceptions, are determined by their Aα-spectra.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 2; 677-690
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of organic cultivation pattern on tomato production: plant growth characteristics, quality, disease resistance, and soil physical and chemical properties
Autorzy:
Feng, X.
Xu, Y.
Liu, D.
Peng, L.
Dong, J.
Yao, S.
Feng, Y.
Feng, Z.
Li, F.
Hu, B.
Powiązania:
https://bibliotekanauki.pl/articles/12703546.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Opis:
Tomato (Solanum lycopersicum L.) is one of the world’s most important cultivated vegetable. In the traditional cultivation methods, the excessive use of pesticides and fertilizers leads to an imbalance of nutrient elements in the soil, an increase in pests and diseases and a decrease in vegetable quality and yield. In the face of increasingly serious environmental and food problems, organic agriculture is considered to be an effective solution. In this experiment, the effects of organic cultivation patterns on the growth, quality, disease resistance in tomatoes, and the physical and chemical properties of soil were studied by different treatments. The results showed that the application of effective microorganisms (EM) bio-organic fertilizer in the cultivation process can significantly improve the yield, quality, and antioxidant enzyme activity of tomato. The use of straw mulching was found to significantly increase the growth, chlorophyll content, transpiration rate, and soluble sugar content of tomatoes. The application of EM bio-organic fertilizer or straw mulching significantly increased the activity of antioxidant enzyme and the expression of LeCHI gene in tomato leaves and enhanced tomato resistance to diseases. Organic production practices were found to significantly improve the soil.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2020, 19, 1; 71-84
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemical destruction of 4-bromochlorobenzene with CaO. Efficiency, kinetics, and mechanism
Autorzy:
Hu, Jun
Feng, Zhuohuan
Huang, Zhiyong
Yu, Jianming
Liu, Jiansheng
Powiązania:
https://bibliotekanauki.pl/articles/208274.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
calcium oxide
4-bromochlorobenzene
mechanochemical destruction
kinetics
tlenek wapnia
4-bromochlorobenzen
niszczenie monochemiczne
kinetyka
Opis:
The degradation of 4-bromochlorobenzene (4-BCB) containing both chlorine and bromine by mechanochemical destruction (MCD) using CaO powder was investigated. The degradation efficiency of 4-BCB almost achieved 100% after 2 h milling. The debromination rate (0.41 h–1) was higher than the dechlorination rate (0.31 h−1) which can be ascribed to the lower dissociation energy of C–Br bond than that of C–Cl bond in 4-BCB. The kinetic analysis demonstrates that nucleation growth was the control step of dehalogenation reactions. Additionally, the dehalogenation efficiency increased with increasing rotate speed and milling ball weight. The XRD and FT-IR spectra analysis manifests that the CaO powder was transformed to CaCl2, CaBr2, Ca(OH)2, and CaCO3. The identification of intermediates and analysis of Raman spectra indicates that the 4-BCB degradation by MCD treatment using CaO powder may occur through three pathways: (a) breakup of the benzene ring to form small molecular halogenated hydrocarbons and mineralization to form CO2 and H2O in sequence, (b) dehalogenation reaction to form benzene and monohalogenobenzene and addition reaction of halogen radicals to form dihalogenobenzenes in sequence; (c) polymerization reaction to form biphenyl, halogenated biphenyl, and graphite.
Źródło:
Environment Protection Engineering; 2020, 46, 2; 63-77
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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